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Masahiko Terao, Junji Watanabe, Akihiro Yagi, Shin'ya Nishida; Improvement of chromatic temporal resolution during smooth pursuit eye movement. Journal of Vision 2008;8(6):663. doi: 10.1167/8.6.663.
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© ARVO (1962-2015); The Authors (2016-present)
When image motion is produced on the retina either by an objects' movements or movements of an observer's eyes, temporal signal integration in subsequent processing could lead to image motion blur. Nevertheless, the perceived image appears to be relatively clear. One mechanism possibly responsible for this motion deblurring is neural integration of visual signals along the motion trajectory, as well as at the same retinal location. In agreement with this hypothesis, different colors presented at the same retinal location, but along separate motion trajectories, are veridically segregated more than expected from local chromatic flicker fusion (Watanabe & Nishida, 2007). Here we report that this improvement of temporal resolution, which had been demonstrated only for object movements, is further enhanced when observers view physically stationary patterns while making smooth pursuit eye movements. We presented on a dark background two arrays of evenly-spaced yellow bars, one above and the other below the fixation point. In the pursuit condition, the fixation point moved at 16 deg/s for 20 deg from the left end to the right end of the CRT screen. When the fixation point reached the screen center area, one of the arrays briefly changed into a red-green alternating grating. The observers had to indicate in which array the color change occurred. The retinal red-green alternation rate varied between 13.3 to 27.1 Hz depending on the inter-bar spacing. In the object-motion condition, the observers viewed moving bar arrays while fixating on a stationary point, and detected a similar color change. The result shows that the detection of a red-green signal, which requires temporal resolution of the two colors, is better in the pursuit condition than in the object-motion condition. This indicates that motion deblurring during pursuit not only suppresses subjective blur (Bedell & Rott, 1996), but also improves objective temporal resolution.
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